This invention relates to a method, system and product for synthesizing sound using encoded audio signals.
To more efficiently transmit digital audio data on low bandwidth data networks, or to store larger amounts of digital audio data in a small data space, various data compression or encoding systems and techniques have been developed. Many such encoded audio systems use as a main element in data reduction the concept of not transmitting, or otherwise not storing portions of the audio that might not be perceived by an end user. As a result, such systems are referred to as perceptually encoded or xe2x80x9clossyxe2x80x9d audio systems.
However, as a result of such data elimination, perceptually encoded audio systems are not considered xe2x80x9caudiophilexe2x80x9d quality, and suffer from processing limitations. To overcome such deficiencies, a method, system and product have been developed to encode digital audio signals in a loss-less fashion, which is more properly referred to as xe2x80x9ccomponent audioxe2x80x9d rather than perceptual encoding, since all portions or components of the digital audio signal are retained. Such a method, system and product are described in detail in U.S. patent application Ser. No. 08/771,790 entitled xe2x80x9cMethod, system and product For Lossless Encoding Of Digital Audio Dataxe2x80x9d, which was filed on the same date and assigned to the same assignee as the present application, and is hereby incorporated by reference.
However, due to the quantity of calculations associated with synthesizing high quality sounds such as voice or music, such synthesis is typically performed using dedicated linear audio (e.g., LPC) digital signal processors (DSP), analog systems, hybrids, or other systems. For example, a DSP linear digital audio equivalent of an analog music synthesizer with two oscillators, a voltage-controlled filter and a voltage-controlled amplifier requires four powerful signal processing algorithms for each musical xe2x80x9cnote.xe2x80x9d Moreover, algorithms such as dynamic cutoff frequency digital filters are at this point considered inferior to analog.
Thus, there exists a need for a method, system and product for synthesizing sound using encoded audio signals, particularly perceptually encoded audio signals. Such a method, system and product would permit any form of sound, voice or music synthesizer to be easily generated with much less effort than deployment in any other form of medium, such as linear digital audio, analog systems, hybrids, or others. Such a method, system and product could also provide for sound synthesis with less delay than associated with a perceptual audio encoder and decoder loop.
Accordingly, it is the principle object of the present invention to provide a method, system and product for synthesizing sound using encoded audio signals, particularly perceptually encoded and component audio signals.
According to the present invention, then, a method is provided for synthesizing sound using encoded audio signals. The method comprises selecting a spectral envelope, and selecting a plurality of frequency subbands, each subband having sample data associated therewith. The method further comprises generating a synthetic encoded audio signal having a plurality of frequency subbands, the subbands having the selected spectral envelope and the selected sample data.
A system for synthesizing sound using encoded audio signals is also provided. The system comprises a controller for selecting a spectral envelope and a plurality of frequency subbands, each subband having sample data associated therewith. The system further comprises control logic operative to generate a synthetic encoded audio signal having a plurality of frequency subbands, the subbands having the selected spectral envelope and the selected sample data.
A product for synthesizing sound using encoded audio signals is also provided. The product comprises a storage medium having computer readable programmed instructions recorded thereon. The instructions are operative to generate a synthetic encoded audio signal having a plurality of frequency subbands, the subbands having a selected spectral envelope and selected sample data.
These and other objects, features and advantages will be readily apparent upon consideration of the following detailed description in conjunction with the accompanying drawings.